While quarterback competitions are typically front-and-center during Pac-12 spring practices, there are always other interesting spring storylines.

Here are two.

USC coach Lane Kiffin enters the spring with several new assistants, a new defensive scheme, and uncertainty at quarterback.

Ted Miller: It was a horrible, no-good, rotten, very bad 2012 season for USC coach Lane Kiffin. And the 2012-13 offseason has been no picnic either. Some Trojans fans wanted Kiffin fired. Just about all were frustrated. Justifiably so, by the way.

Lane: Welcome to spring, the season for rebirth! Time to turn the page. Or, perhaps, pick up an entirely new book.

At the very least, the situation at USC is interesting. One of the nation's premier programs is front-and-center for many of the wrong reasons, but there is enough talent on hand for Kiffin to turn things around and shut up his critics.

Interesting plot lines? Kiffin will be breaking in four new assistant coaches, including a pair of new coordinators, his defense will be transitioning from a 4-3 base to a 3-4, and he's looking for a new quarterback for the first time in his tenure.

What if Clancy Pendergast shakes things up and, suddenly, the defensive guys are playing hard and fast in a sound scheme they understand? And what if the offense, nonetheless, makes plenty of plays because the quarterbacks are sharp and the line is manning up? What if the fitness level of the Trojans improves? What if offensive tackle Aundrey Walker breaks through, realizing his future NFL contract will be based on performance, not measurables? What if Devon Kennard proves a perfect fit as a 3-4 outside linebacker, as we believe he is? What if guys like Marqise Lee, Hayes Pullard, Silas Redd, Dion Bailey and Kevin Graf step up as leaders? What if receivers George Farmer and Victor Blackwell decide they don't want to be left in the dust behind Lee and Nelson Agholor? What if running back Tre Madden says, "Hey, remember me?"

What if Kiffin simultaneously refocuses and relaxes? What if he uses his capable brain to be smart, not a smart aleck, to be creative, not sneaky? What if he realizes the media is not an enemy, but just a bunch of folks trying to do their job whom he should humor with vague though sometimes amusing answers?

There are a lot of "What ifs?" with USC and Kiffin. It's not difficult, by the way, to talk yourself into believing a bounce-back is entirely possible.

That's what is interesting. Kiffin 2.0 was 2010 and 2011, when he seemed to find his rhythm as a coach after controversial stints with the Oakland Raiders and Tennessee Volunteers. Kiffin 3.0, was 2012, a complete face-plant.

This spring presents us with Kiffin 4.0. It could prove to be the most important transition of his career as a head coach.

And that is interesting.

Kevin Gemmell: Besides quarterback battles -- which I think are always the most exciting position battles there are -- I'm most curious to see how the running back battle is going to play out at Stanford.

When you look at a Stanford squad that is very heavy on upperclassmen -- on both sides of the ball -- you have to wonder if all of the pieces are in place for Stanford to make a legitimate run at the national championship.

I wasn't sure before, but with the addition of Tyler Gaffney to the running back corps, I'm warming up to the idea that the Cardinal could challenge any team in the country for a BCS championship -- if they can get out of their own conference (or division for that matter) -- which anyone will tell you is no easy task.

It's no surprise that Stanford's primary offensive weapon is the quarterback. Not because of what he does with his arm -- but because of what he does when he goes under center -- checking out of bad plays and putting the offense in the best possible play against the defense shown. This allows running backs to flourish. Andrew Luck was phenomenal at it. Kevin Hogan should get better.

So, when Hogan turns to handoff on power right or power left, who is going to be the primary ball carrier? Anthony Wilkerson has shown bursts and outstanding top-end speed. But injuries have slowed him, and playing behind Stepfan Taylor the past few years didn't allow him to really break out following his strong true freshman season. Gaffney is a rock and hard to bring down. He's the kind of guy who could carry the ball 10 times for 4.5 yards a pop.

Barry Sanders is an interesting X-factor. He obviously was a high-profile recruit because of his name -- but beyond that, he's supposedly a pretty darn good back. Maybe he ends up winning the job and can be a 15-carry type of guy.

Then you have Ricky Seale, a shifty runner with great vision who has been trapped at the bottom of the depth chart, but continues to receive praise from David Shaw. Remound Wright and hybrid Kelsey Young are also in the mix.

Whoever is Shaw's go-to back, he'll have the benefit of running behind an outstanding offensive line that is only going to get better with David Yankey -- an All-American and last year's Morris Trophy winner -- moving back to his natural position at guard. And Shaw has said he plans to keep Ryan Hewitt at fullback -- giving the running backs a cadre of blockers that rivals any other in the country.

By season's end, this could be your national championship team. The question is, which back will carry it there?